Drain for floating roof tanks



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June 24,l 1952 Patented June 24, 1952 VDRAIN FOR FLOATING ROOF TANKS Frederick D. Moyer, Chicago, Ill., assignor to Chicago Bridge & Iron Company, a corporation of Illinois Application October 16, 1948, Serial No. 54,922

4 Claims.

This invention relates to a drain and more particularly to a drain for a floating roof tank.

Drainage means must be provided for a iioating roof tank designed for use in an area where precipitation is to be expected. Generally such drains comprise a sump in the floating roof toward which the deck of the roof is inclined. In some installations the sump opens directly under the roof to the stored product and rain water, being heavier than products commonly stored in such tanks, will eventually nd its way to the bottom. This particular form of drain is undesirable as it takes some time for all the water to reach the bottom of the tank with the result that the stored product` is water-contaminated for a good part of the time.

It has been proposed to alter this type of drain by the use of a flexible or bendable drain hose connected to the sump and opening to the bottom of the tank. In such installations a 4" to 6 layer of water is maintained on the bottom of the tank and means may be provided at the side of the tank for draining ofi the water as it accumulates on the bottom.

It has also been suggested to connect a iiexible or bendable pipe directly from the sump to the exterior of the tank in order that the tank contain no free water at any time.

In any of the above installations the drain may comprise a flexible hose or a jointed pipe, either of which drains are referred to herein as bendable drains.

Experience has shown that one of the first ele ments to wear out on a floating roof tank is the drain and it has heretofore been necessary to empty the entire tank in order that a worn out drain may be replaced. Bendable drains also cause difficulty when they are used in floating roof tanks in areas where freezing weather occurs. In such areas the water overlying the bottom of the tank often freezes and if during such freezing the drain is at least partially resting upon the bottom, as it does when the roof is at some position other than its highest position, the drain itself will become imbedded in the ice and will rupture if further liquid is introduced into the tank causing the roof to rise.

I have invented and am herein disclosing and claiming a drain for a floating roof tank which eliminates the diiculties above referred to. By this invention I provide a drain which may be repaired or replaced without taking the tank out of operation and I further provide means for maintaining the drain above thebottom of the tank at all times during operation of the tank so as to prevent freezing of the drain to the bottom.

The invention will be described in conjunction with the specific embodiment shown in the accompanying drawings in which:

Referring now to the drawings I show a floating V roof ID being in the form of a double deck roof having an upper deck II and a lower deck I2. The upper deck slants downwardly toward a sump I3 and is provided with a manhole I4 opening through the roof. A circular plate I5 is connected to the sides of the sump I3 and provided with a central circular opening I6. A drain connection I1 is firmly attached to a second circular plate I8 positioned over and secured to the plate I5 and provided with an opening I9 through which rain Water may drain. Connected to the member I'I is a flexible drain hose 2.

Resting upon the bottom 2| of the tank directly beneath the sump I3 is a platform 22. In the specific embodiment shown, the platform comprises a plurality of rods 23 radiating outwardly from a central metallic disk 24, attached to a pipe section 34, to form a foraminous bottom for the platform. The pipe 34 is centered over a pipe section 35 upstanding from the bottom of the tank to maintain the platform 22 centered beneath the sump. Adjacent the outer edge of the platform the rods are bent degrees upwardly to form an upstanding edge 25 and are then bent degrees so that they extend downwardly to the bottom of the tank to support the bottom of the platform above the tank bottom. A circular rod 26 encircles the platform and is connected to the rods 23 at the point where they are curved 180 degrees. The distance from the platform to the tank bottom normally is from 6 to 3" and in any event is sufficient to maintain the bottom of the lplatform above the lcevel of any water overlying the bottom of the ank.

A pipe 2i is xed to the bottom of the tank and provided with a drain opening 28. Upstanding from the pipe 2l is a member 29l adapted to be connected to the pipe by means of a bayonet clamp SII. The member 29 is positioned directly beneath the manhole I4 and is provided with a handle 3l by which it may be grasped by a workman standing on top of the deck when the roof is in the position shown in Fig. l. At this point the roof normally will be resting upon its support rather than being supported directly by the liquid within the tank although it is clear that by adjusting the length of the member 29 that member can be made accessible from the manhole when the roof is in a slightly higher position and floating on the liquid. A workman on the roof may then reach down through the manhole 4by the platform.

and grasp the handle 3| to rotate the member 29 approximately one-quarter turn whereupon the member may be withdrawn from the pipe 2l and out throughthe manhole.

The member 29 is also provided with a fitting 32 adapted to be secured to a corresponding tting 33 secured to the lower end of lthe hose 25 and drain water coming down the hose is lead out to the bottom of the tank through the opening 28. The fittings 32 and' 33 are secured together so as to impart no twist to the hose when the roof is in its lowest position in the tank. When the roof rises the hose will twist through a number of degrees determined by the amount of loops inthe hose when it is entirely supported I Yprefer `to arrange the platform 'and the hoseso that when the roof is in Vits vlowest; position the hose is in a single complete loop and therefore movement of the roof from its lowest to lits highest position will twist the h'ose through'360 degrees. The torsionalV effect so exerted on the hose insures that it will form a single loop upon the downward movement of 'the roof within thetank. rI'he diameter of the platform then is approximately equal to the diameter of the-'loop formed by the hose. This will be approximately the totaldistance of verti- `call-movement 'of the roof divided by p-i.

' The-customary c ain outlet may used to ldrain out water which accumulates on the tank bottom. The outlet may be automatically or manually operated so as to prevent water from rising to a point high enough to come into contactwith the hose.

When itbecomes desirable to replace the vd, 'the'cover (not shown) of the manhole lll may be removed and the member 2d withdrawn through the manhole as just described. This, ofcourse', will bring the-lower end of the hose 2B out upon the deck. The lupper end of the new hose may then be secured to the fitting 3.3 on the .end of the old hose dropped down into the tank. Removal of the plate I8 and withdrawal of the connection il and the upper 'end of the hose through the sump IES vmay th'enbe accomplished and the old hose may be entirely withdrawn through the sump; such action, of course,` will draw the new hose thereafter. The upper end of the new hose may then be connected to the member il and the i `lower end connected to the member 2i? and both of said members may be replaced in the tank. In such manner a defective or damaged hose may-'be replaced without the necessity of completely draining the tank'without the necessity of-` sending aman under the roof.

The purpose of the platform 22 is to main-V tain the drain above the bottom of the `tank inail positions of the roof. To that end I so proportion and locate the platform that the drain is` held within the confines thereof with downward movement of the roof. IThus, for a central drain the platform is located in the center-of the'bottom and is generally located directly beneath the sump to which the drain is attached.

@While I have shown and described my in- -vention in its preferred Vembodiment it should be understood that it is capable of many modifications. I therefore do not intend to be limited to the exact embodiment shown but rather' intend that my invention `be construed broadly 4 in accordance with the spirit and scope of the appended claims.

`Iclaimzl. In a floating roof vtank having a floating roof, and a sump and manhole inthe roof,

Adrainage means for the roof comprising a bendable drain having one end connected to the sump, an upstanding member fixed to 'the bottom of thetank a removable member extending upwardly above the bottom of the tank beneath the manhole and having clamping means for vremovably securing said members together, and means for attaching the other end of the drain to the removable member, said drain being in an untwisted condition when the roof is in its lowest position. within the tank.

2.1m a floating roof tank having a floating roof, anda sump and a manhole in the roof, drainage means comprising a bendabledrain having one end i'ixedly connected to the sump, a platform spaced above the bottom of the tank beneath the drain and a removable member `upstanding above the platform at all positions of the roof within the tank'and said member having the other end of the drain xedly attached thereto, said member being accessible from and removable through said manhole when the roof is floating nearthe bottom of they tank and means for supporting said platform abovethe bottom to support the drain abovewater in the bottom of the tank at all times during normal operation of the tank, said platform supporting the drain in an untwisted coil when the roof is in its lowest position in the tank.

3. In a floatingV roof tank having a floating roof, and a sump and a manhole in theroof, drainage means. for the roof comprising a bendable drain having one end connected to the sump, an upstandng pipe fixed to the bottom of the tank and having openings therein adjacent said bottom, a member extending upwardly from said .pipe and having clamping means for removably attaching said member to said pipe, said member and pipe being located beneath the manhole, and means for attaching the other -end of the drain to said member, said attaching means being spaced from the bottom `of the tank when said member is attached to'said upstanding pipe.

4. Apparatus of theV character described in claim 3 in which 'support means are provided for the vdrain comprising a platform spaced above the bottom of the tank and positioned beneath said drain and means for supporting said vplatform above the bottom of the tank, said platform having a foraminous .bottom with an upstanding peripheral edgeto receive and maintain substantially the entire drain out of contact with the bottom of the tank.

FREDERICK D. NLOYER.

REFERENCES CITED The following references are of record the le of this patent:

UNITED STATES PA'IENTS 

